1. Field of the Invention
This invention relates to the production of molded polyurethane products.
2. Description of the Prior Art
The particular crosslinker which is found to be advantageous for use in semiflexible energy absorbing foams of this invention has been described as a detergent in U.S. Pat. No. 2,998,452.
U.S. Pat. No. 4,137,265 discloses the Mannich condensate precursor of the crosslinker of the present invention. This patent describes and claims a polyol which is a propylene oxide adduct of the Mannich condensate precursor for use in forming rigid polyurethane foams. U.S. Pat. No. 4,137,265 discloses and claims the propylene oxide adduct of nonyl phenol, formaldehyde and diethanolamine. This product is useful as the polyol for rigid foams. It was surprisingly discovered that the ethylene oxide adduct of the Mannich condensate found particular advantage in formulations for semiflexible foams.
The automotive industry, in particular, is constantly seeking new technologies for increasing the safety of vehicles, while, at the same time, decreasing the weight of the vehicles. A major part of the safety program in the automotive industry is the use of molded polyurethane foams which absorb energy upon impact. The present invention presents an improved method of preparing molded polyurethane foam which in addition to absorbing impact, are lighter in weight resulting in less vehicle weight.